Better version; http://www.ivorcatt.co.uk/x8cktony.pdf

 

The Betrayal of Science

Oliver Heaviside

327 ELECTROMAGNETIC THEORY. Vol. 1, 1893, CH. IV,

 If you have got anything new, in substance or in method, and want to propagate it rapidly, you need not expect anything but hindrance from the old practitioner even though he sat at the feet of Faraday. Beetles could do that. Besides, the old practitioner is apt to measure the value of science by the number of .dollars he thinks it is likely to bring into his pocket, and if he does not see the dollars, he is very disinclined to disturb his ancient prejudices. But only give him plenty of rope, and when the new views have become fashionably current, he may find it worth his while to adopt them, though, perhaps, in a somewhat sneaking manner, not unmixed with bluster, and make believe he knew all about it when he was a little boy. 

He sees a prospect of dollars in the distance, that is the reason.

338 ELECTROMAGNETIC THEORY. CH. IV.

The perfect obstruction having failed, try the perfect conduction. You should make your converts out of the rising generation and the coming men. – Oliver Heaviside

[Heaviside is wrong here. “The coming men” are only interested in passing exams, and dislike uncertainty. – IC 27.1`2.2018]

http://www.ivorcatt.co.uk/wxyz.pdf

http://www.ivorcatt.co.uk/44.htm

http://www.electromagnetism.demon.co.uk/news2000.htm

 

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http://www.ivorcatt.co.uk/x231.pdf

The Instrumentalist’s Manifesto

Tue, Dec 18, 10.21 PM

Professor Tony Davies was on the Board of Directors of the IEEE, 400,000 members, the senior institution for electromagnetic theory.

Tony Davies,

 

https://mail.google.com/mail/u/0/images/cleardot.gif

https://mail.google.com/mail/u/0/images/cleardot.gif

to me, Alex, Christopher, Malcolm, Davidhttps://mail.google.com/mail/u/0/images/cleardot.gif

For what it is worth, just a brief comment based on a quick read of this:

While I was an electrical engineering undergraduate at Southampton University (from where I left with a BSc(Eng) in 1961 to go to GEC in Coventry,  it was my understanding that Theory H was the 'correct one'. and I have not had any reason so far to change that view.  That is not to say the Theory H is correct, there might be something better, but I do not know enough of field theory to decide about that.

As I have mentioned before my 'roots' are in circuit theory which I have never claimed to be a description of reality, but is an extremely helpful basis for designing useful things, which have performance close enough to the results from circuit theory that this is sensible and for many applications remains the best way to get to those useful outcomes.  Do not forget that since there is no distance dimension in circuit theory, a transmission line approximated by one thousand ideal capacitors and inductors (of the text book type) can easily be fitted on to the point of a very sharp pin (and there is stilll room for all those medieval angels as well, if you choose to also believe in that).

Perhaps some would wonder why Theory N persists if it is incorrect. Leaving out the complexity of understanding what ExH means, and describing electricity by analogy with water flowing through pipes, etc. has been and still is, a sufficient explanation for many amateur and professional electrical technicians who have to install and repair electrical installations in buildings and understand the IET Wiring Regulations, etc.   For the general non-scientific public it is probably better to tell them that electricity is a flow of electrons and that these can move quite freely in a conductor, making it warm in the process, and melting it if there is too much current because it gets too warm.   Such ideas are helpful in other situations such as the design of water-based piped central heating systems where the designer has to work out the required pump pressure (like voltage) and the diameter of the pipes (like resistors) in order to carry the required water flow (like current) to the radiators (which are actually producing most of their heat by convection rather than radiation).   It is only necessary to know that the 'resistance' has a square law relationship to pump pressure and water flow to understand that the iterative calculations done by central heating designers are what an electric circuit engineer would do to analyse electrical resistive networks made up of square law resistors - e.g. it is not just linear simultaneous equations, one has to use an iterative method such as Newton-Raphson (which, of course is unknown to most central heating installers). https://en.wikipedia.org/wiki/Newton%27s_method

I hope that all this gives you something nice to dream about over the coming holiday season.

Tony Davies

2018 Dec 18th

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http://www.ivorcatt.com/2607.htm

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How many angels can dance on the head of a pin?

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Dancing angels

The question How many angels can dance on the head of a pin?" " (alternatively "How many angels can stand on the point of a pin?"[1]) is a reductio ad absurdumof medieval scholasticism in general, and its angelology in particular, as represented by figures such as Duns Scotus and Thomas Aquinas.[2][3] It is first recorded in the 17th century, in the context of Protestant apologetics. The question has also been linked to the fall of Constantinople, with the imagery of scholars debating about minutiae while the Turks besieged the city.[4][5] In modern usage, it therefore has been used as a metaphor for wasting time debating topics of no practical value, or questions whose answers hold no intellectual consequence, while more urgent concerns accumulate.[1][4]

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Electromagnetism for Engineers: An Introductory Course (Textbooks in ...



https://www.amazon.co.uk/Electromagnetism-Engineers-Introductory.../0198562993

 

1.      

Percy Hammond is Honorary Research Professor at Southampton, and is a very distinguished figure in the circles of electromagnetic scholarship. This book is ...

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https://archive.org/stream/electromagnetict01heavrich/electromagnetict01heavrich_djvu.txt - Oliver Heaviside

But the old established practitioner with prejudices, who could not

see the reason, was put into a position of some difficulty

resembling chancery. If you have got anything new, in

substance or in method, and want to propagate it rapidly,,

you need not expect anything but hindrance from the old

practitioner even though he sat at the feet of Faraday.

Beetles could do that. Besides, the old practitioner is apt

to measure the value of science by the number of .dollars-

he thinks it is likely to bring into his pocket, and if he

does not see the dollars, he is very disinclined to disturb his

ancient prejudices. But only give him plenty of rope, and

when the new views have become fashionably current, he may~

find it worth his while to adopt them, though, perhaps, i

a somewhat sneaking manner, not unmixed with bluster, and

make believe he knew all about it when he was a little boy t

He sees a prospect of dollars in the distance, that is the-

 

 

 

338 ELECTROMAGNETIC THEORY. CH. IV.

 

reason. The perfect obstruction having fciiled, try the perfect conduction.

 

You should make your converts out of the rising generation

and the coming men. Thus, passing to another matter, Prof.

Tait says he cannot understand my vectors, though he can

understand much harder things. But men who have no quater-

nionic prejudices can understand them, and do. Younger

men are born into the world with more advanced ideas, on

the average. There cannot be a doubt about it. If you had

taught the Calculus to the ancient Britons you would not

have found a man to take it in amongst the whole lot, Druids

and all. Consider too, what a trouble scientific men used

to have with the principle of the persistence of energy. They

could not see it. But everybody sees it now. The important

thing is to begin early, and train up the young stick as you

want it to grow. Now with Quaternions it is different.

You may put off till to-morrow what you cannot do to-day,

for fear you commence the study too soon. Of course, I"

refer to the Hamilton-Tait system, where you have to do

violence to reason by making believe that a vector is a

quaternion, and that its square is negative.

 

According to Ohm's law alone, a perfect conductor should be

one which carried an infinite current under a finite voltage,

and the current would flow all through it because it does so

ordinarily. But what is left out of consideration here is the

manner in which the assumed steady state is established. If

we take this into account, we find that there is no steady state

when the resistance is zero, for the variable period is infinitely

prolonged, and Ohm's law is therefore out of it, so far as the

usual application goes. In a circuit of no resistance containing

a finite steady impressed voltage E, the current would mount

up infinitely and never stop mounting up. On the other hand,

if we insert a resistance R in the former circuit of no resistance,

there will be a settling to a steady state, for the current in the

circuit will tend to the value E/R, in full obedience to Ohm's

law. The current is the same all round the circuit, although

a part thereof has no resistance. We conclude that that

portion has also no voltage.

 

But this is only a part of the story. Although we harmonise

with Ohm's law, we overlook the most interesting part. The

 

 

 

THEORY OF PLANE ELECTROMAGNETIC WAVES. 339

 

smaller the resistance the greater the time taken for the

current to get into the conductor from its boundary, where it

is initiated. In the limit, with no resistance, it never gets in

at all. Where, then, is the current? For, as we have said,

it mounts up to a finite value if there be a finite resistance

inserted along with the perfect conductor, and mounts up

infinitely if there be no resistance.

 

We recognise the existence of electric current in a wire by

the magnetic force round it, and in fact measure the current

by its magnetic force. Therefore, according to this, there is

the same total current in the wire, if the magnetic force out-

side it remains the same. If, then, the magnetic force stops

completely at the surface of the wire, whose interior is entirely

free from magnetic force, the measure of the current is just

the same. The uniformly distributed current of the steady

state appropriate to finite conductivity becomes a mere surface

current when the conductivity is infinite. In one case we

have a finite volume-density of current, and in the other a

finite surface-density. When the current inside the wire is

zero so is the electric force, in accordance with Ohm's law

again. The electric and magnetic phenomena are entirely in

the dielectric outside the wire, the entrance of any similar

manifestations into it being perfectly obstructed by the absence

of resistance. For this purpose the thinnest skin would serve

equally well. In the usual sense that an electric current is a

phenomenon of matter, it has become quite an abstraction, for

there is no matter concerned in it It is shut out completely.

In the circuit of finite resistance, a portion of which is a wire

of no resistance, supporting a steady current, there is no

difference whatever in the external, magnetic force outside the

resisting and non-resisting parts, though in one case there is

entrance of the magnetic force and waste of energy, whilst in

the other there is no entrance and no waste. These con-

clusions do not rest upon Maxwell's theory of dielectrics, but

upon the second circuital law of electromagnetism applied to

conductors. But it is only by means of Maxwell's theory that

we can come to a proper understanding and explanation of the

functions of conductors.

 

The sense in which a perfect conductor is a perfect con-

ductor in reality as well as in name is that it allows electro-

 

z2

 

 

 

310 ELECTROMAGNETIC THEORY CIL IV.

 

magnetic waves to slip along its surface in a perfectly free-

manner, without waste of energy. Though perfectly obstruc-

tive internally, it is perfectly conductive superficially. It

merely guides the waves, and in this less technical sense of

conduction the idea of a perfect conductor acquires fresh life.

 

The Effect of a Perfect Conductor on External Disturb-

ances. Reflection and Conduction of Waves.

 

190. The conditions at the interface of a perfect conductor

and a dielectric are that the electric force in the dielectric has-

no tangential component and the magnetic induction no normal

component. Or

 

VNE = 0, NH = 0,

 

if N be the unit normal from the conductor. Thus, when

there is electric force at the boundary it is entirely normal,

with electrification to match ; and if there is magnetic force it

is entirely tangential, with electric current to match. Both

electrification and current are superficial. The displacement

measures the surface density a- of the one, and the magnetic*

force that of the other, say c, thus

 

<r = ND, c = VNH,

 

in rational units, without any useless and arbitrary 4?r constant,,

such as is required in the B.A. system of units, of amazing

irrationality. If, then, we have electromagnetic disturbances

given in a dielectric containing a perfect conductor, the latter

first of all is free from disturbance, and next causes such re-

flected waves as to annihilate the tangentiality of the electric

force and the normality of the magnetic force.

 

As regards steady states, the influence of a perfect conductor

on induction due to foreign sources is to exclude it in the same

manner as if the inductivity were made zero ; that is, the induc-

tion goes round it tangentially instead of entering it. This

is usually ascribed to an electric current-sheet induced upon it&

surface, whose internal magnetic force is the negative of that

due to the external field. This is right mathematically, but is

deceptive and delusive physically. There is no internal force,,

neither that of the external field nor that of the superficial

current. The current sheet itself merely means the abrupt

 

 

 

THEORY OF PLANE ELECTROMAGNETIC WAVES. 341

 

stoppage of the magnetic field, and cannot really be supposed

to be the source of magnetic force in a body which cannot

permit its entrance. The previously mentioned case of a per-

fectly conducting wire inserted in a circuit of finite resistance

supporting a steady current, will serve to bring out this point

strongly. The supposed induced superficial current is now

actually the main current in the circuit itself.

 

It is different with the steady state due to external electric

sources. The displacement is just as much shut out from the

perfect conductor (which may also be a dielectric) as was the

magnetic induction, but in a strikingly different manner, ter-

minating upon it perpendicularly, as if it entered it in the

manner that would happen were the conductor nonconducting,

but of exceedingly great permittivity, so that it drew in the

tubes of displacement.

 

Although a perfect magnetic conductor is, in the absence of

knowledge even of a finite degree of magnetic conductivity, a

very far-fetched idea, yet it is useful in electromagnetic theory

to contrast with the perfect electric conductor. A perfect

magnetic conductor behaves towards displacement just as a

perfect electric conductor does towards induction ; that is, the

displacement goes round it tangentially. It also behaves

towards induction as a perfect electric conductor does towards

displacement ; that is, the induction meets it perpendicularly,

as if it possessed exceedingly great inductivity, without

magnetic conductivity. This magnetic conductor is also per-

fectly obstructive internally, and is a perfect reflector, though

not quite in the same way as electric conductors. The tan-

gential magnetic force and the normal electric force are zero.

 

As regards waves, there are two extreme ways in which a

perfect conductor behaves that is, extreme forms of the gene-

ral behaviour. It may wholly conduct them, or it may wholly

reflect them. In the latter case we may illustrate by ima-

gining a thin plane electromagnetic sheet, consisting of crossed

electric and magnetic forces in the ratio given by E = /*vH,

moving at the speed of light, to strike a perfect conductor

flush that is, all over at the same time, by reason of parallel-

ism of the sheet and conducting surface. The incident sheet

is at once turned into another plane sheet, which runs away

from the conductor as fast as it came. If the conductivity be

 

 

 

342 ELECTROMAGNETIC TEIEORY. OIL IV.

 

of the electric kind the reflected sheet differs from the incident

in having its displacement reversed, but in no other respect*

This is perfect reflection with reversal of E. During the act

of reflection, whilst the incident and reflected sheets partly coin-

cide, E is zero and H is doubled. Both are tangential ; but

there can be no tangential E, so the reflector destroys E and

initiates the reflected sheet, in which H is the same as in the

incident sheet, whilst E is reversed.

 

On the other hand, when the conductivity is of the magnetic

kind, the reflected wave sheet differs from the incident only in

having its induction reversed. The displacement persists,

being doubled during the act of reflection, whilst the induction

is then annulled.